Conventional techniques for precipitating particles from solution include methods in which a solution is heated in a container to evaporate off and remove the solvent and obtain particles (hereunder referred to as “dry evaporation methods”), methods in which a solution is sprayed into hot air to evaporate the solvent in a gas phase, and precipitate particles as a dry powder (hereunder referred to as “spray dry methods”), and methods in which a solution of a solute dissolved in a good solvent is added dropwise to a heated poor solvent and the good solvent is evaporated off, to obtain a slurry of the particles and the poor solvent (hereunder referred to as “common methods using a good solvent and poor solvent”).
Specific examples of common methods using a good solvent and poor solvent are described in PTL 1. PTL 1 discloses a method for producing 2,2-bis[3,5-dibromo-4-(2,3-dibromopropoxy)phenyl]propane (hereunder abbreviated as TBA-BP), in the form of needle crystals that have excellent thermal stability and storage stability, as well as an improved powder flow property.
Also, PTL 2 provides a diagram illustrating the principle of the publicly known dropping reprecipitation method.